HFCWO. Patients received HFCWO via The Vest Airway Clearance System (Model 205; Hill-Rom). The HFCWO was performed with patients wearing a clothlike vest that covers the entire thorax (front and back) and the upper part of the abdomen. The device was an inflatable vest connected by tubes to an air-pulse delivery system. The HFCWO was conducted as a 15-minute treatment in normal mode with pressure set at +2 mm Hg and frequency at 14 Hz